The present invention relates generally to telecommunications and more specifically to call delivery in wireless and/or dual-mode environments.
Recent advances in telecommunications technology, including without limitation the ever-increasing availability of high-bandwidth data connections (such as broadband Internet access, etc.), have made voice over Internet Protocol (“VoIP”) a feasible alternative for many telephone users. Merely by way of example, a residential subscriber might choose, in lieu of contracting through a Plain Old Telephone Service (“POTS”) provider for voice service, to subscribe only to a broadband Internet connection (e.g., via cable modem, xDSL modem, wireless broadband, WiMAX, WiBro, WiFi, 802.xx, LMDS, etc.) and to contract with a VoIP provider for voice services.
In a typical VoIP system, a subscriber may use any available connection with the Internet (including without limitation, residential and/or commercial Internet connections, wireless “hotspots” in various public locations, Bluetooth connections with Internet-connected devices, etc.) to access, again via the Internet, a VoIP server maintained by a VoIP provider with which the subscriber has contracted. This arrangement provides multiple benefits to the subscriber. For one thing, the connection is portable, in that the user may make and/or receive calls (often using a single telephone number) from virtually any location with a sufficient Internet connection. Additionally, the use of the Internet to route calls often means that the user may obtain flat-rate (and/or low per-minute rate) long-distance and/or International voice service. Moreover, the use of the Internet to route calls allows the subscriber to maintain a “local” telephone number in any desired market where the provider has a point of presence, meaning for example that a subscriber located in Denver may maintain a local telephone number in Seattle, allowing callers in Seattle to reach the subscriber through a local call. Those skilled in the art will appreciate the many other features and enhanced services that may be provided by VoIP service.
In particular, the use of the Internet (and/or any other Internet Protocol (“IP”) connection) to route VoIP calls can provide in substantial gains in efficiency (and thus substantial savings) for both subscribers and providers. Realizing these benefits, subscribers have begun to rely more heavily on VoIP as an alternative (and, in some cases, primary) mode of voice communications. Correspondingly, there is substantial market demand for ever more pervasive and comprehensive VoIP offerings.
One example of this market demand is for dual mode cellular/VoIP service. Those skilled in the art will appreciate that cellular service often carries relatively expensive per-minute charges (and/or monthly minute quotas with expensive overage charges). Cellular subscribers, then, desire the ability to use a single phone (ideally with a single number) in both a cellular network and for VoIP communications (e.g., through a wireless IP connection). Providers have embarked on plans to offer this service, and some phone manufacturers have begun to manufacture “dual mode” phones that can function as both cellular phones and VoIP phones.
To maximize the benefits of such services, subscribers generally desire a dual mode device and/or phone and/or network with the ability to transition seamlessly between cellular and VoIP modes, ideally during a call. For example, if a subscriber receives (inbound) or places (outbound) a VoIP call while accessing a broadband Internet connection (e.g., via WiFi, WiMax, 802.xx, LMDS, etc.) and subsequently (mid-call) loses that connection (either gradually or abruptly), the subscriber would like the call to transition mid-call to the macro cellular network. By the same token, if a subscriber receives (inbound) or places (outbound) a circuit switched cellular call and subsequently (mid-call) acquires a broadband Internet connection (again, perhaps, by traveling within range of a WiFi or WiMax transceiver), the subscriber would often prefer to seamlessly transition mid-call from the cellular network to a VoIP call over the broadband Internet connection, since a VoIP call typically will be less expensive than a cellular call. A typical subscriber, however, would not tolerate the inconvenience of ending the call and re-dialing the other party merely to use the VoIP service instead of the cellular service.
This, however, may present a logistical problem. For instance, if a subscriber originates a call in a cellular network, it may be possible to route the call from a cellular provider to a VoIP provider using a trunk connection, for example, and from the VoIP provider to the desired destination number. When the user obtains an IP connection, the cellular provider may handoff the call to the VoIP provider. One skilled in the art will appreciate, however, that in conventional systems, the trunk connection will remain active for the duration of the call. Even if the subscriber no longer has to pay charges associated with the cellular network, the VoIP provider may be forced to pay charges related to the use of the cellular providers' trunk ports, among other things. Thus, the VoIP provider often will be forced to absorb unnecessary overhead expenses, which may not be directly billable to the subscriber.